Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.37 (neutrophil elastase)
4,078 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pathogenesis of emphysema is considered to be an imbalance of protease and antiprotease activity in the lower respiratory tract leading to uninhibited degradation of lung interstitium by elastolytic enzymes. An increased amount of the serine protease neutrophil elastase (NE) is though to play a major role in this degradation. Because the expression of NE is limited to neutrophil precursors in the bone marrow, we hypothesized that nicotine, which is readily absorbed from lung and distributed to tissue, including bone marrow, would increase expression of the NE gene and protein. HL-60 cells, a myeloblast/promyelocyte cell line, were cultured in the presence or absence of 0.06 and 0.8 microM nicotine for 5 d. Both concentrations of nicotine caused a 2.4- to 3.3-fold increase, respectively, in NE gene expression over unstimulated cells, and NE protein increased 4.8- to 3.4-fold over unstimulated cells, respectively, similar to our positive control DMSO. Nicotine did not induce upregulation of the NE gene by initiating cell differentiation. Both low and high nicotine concentrations upregulate the NE gene in HL-60 cells leading to increased NE protein concentration per cell suggesting a pathophysiologic mechanism for emphysema.
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PMID:Nicotine enhances expression of the neutrophil elastase gene and protein in a human myeloblast/promyelocyte cell line. 891 74

Based on the most recent available crystal structures and biochemical studies of protease complexes of normal and mutant serine protease inhibitors (serpins), we have built models of the complexes: alpha 1-antitrypsin + human neutrophil elastase; alpha 1-antitrypsin Pittsburgh (358Met-->Arg) (Scott et al., J. Clin. Invest. 77:631-634, 1986) + tyrpsin; alpha 1-antitrypsin Pittsburgh (358Met-->Arg) + thrombin; and antithrombin + thrombin. All serpin sequences correspond to human molecules. The models show correct stereochemistry and no steric clashes between protease and inhibitor. The main structural differences in the serpins from the parent structures are: (1) the reactive center loop is inserted into the A-sheet as far as P12; (2) strand s1C is removed from the C-sheet; and (3) the C-terminus has changed conformation and interacts with the protease. In the absence of an X-ray structure determination of a serpin-protease complex, the demonstration that insertion of the reactive center loop into the A-sheet as far as P12 is stereochemically feasible provides structures of a protease-bound conformation of intact serpins with which to rationalize the properties of mutants, guide the design of experiments, and form a basis for further modeling studies, such as the investigation of the interaction of heparin with serpin-protease complexes.
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PMID:Modeling of serpin-protease complexes: antithrombin-thrombin, alpha 1-antitrypsin (358Met-->Arg)-thrombin, alpha 1-antitrypsin (358Met-->Arg)-trypsin, and antitrypsin-elastase. 895 50

Secretory leukoprotease inhibitor (SLPI) is one of the major physiological inhibitors protecting respiratory epithelium from attack by excess human leukocyte elastase (HLE), a serine protease released by neutrophils upon activation in response to inflammatory stimuli. Reaction with N-chlorotaurine, a major long-lived oxidant generated by activated neutrophils, oxidized all four methionine residues, but no other amino acids, in SLPI, resulting in substantial diminution of its elastase inhibitory activity. Oxidation of the P1' residue, Met73, accounted for most of the diminution in activity since a site-directed mutant of SLPI with leucine at the P1' position retained much higher residual activity after reaction with N-chlorotaurine. The diminished activity of oxidized SLPI could be almost completely restored when an iduronate-containing glycosaminoglycan, such as heparin, heparan sulfate, or dermatan sulfate, was added to the reaction medium. Addition of a sulfated glucuronate-containing glycosaminoglycan, chondroitin 4- or 6-sulfate, to the medium resulted in smaller but significant restoration of the lost activity, whereas the effects of hyaluronic acid and keratan sulfate were negligible. Kinetic analysis revealed that glycosaminoglycans greatly accelerated the association of oxidized SLPI and HLE, whereas iduronate-containing glycosaminoglycans also stabilized the enzyme-inhibitor complex formed. Based on these findings, we suggest that oxidized SLPI is a functionally active form of the inhibitor but that expression of its elastase inhibitory activity is regulated by sulfated uronate-containing glycosaminoglycans. Because its methionine residues have already been oxidized, this form of SLPI is resistant to the oxidant species that selectively attacks methionine residues in proteins. These findings indicate that SLPI may play a previously unexpected role in elastase inhibitory function in the lungs when significant inflammation is present.
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PMID:Glycosaminoglycans regulate elastase inhibition by oxidized secretory leukoprotease inhibitor. 912 11

YM-47141, a peptidic compound recently isolated from Flexibactor sp. Q17897, strongly inhibited human leukocyte elastase (HLE) with Ki value 2.1 x 10(-7) M. Unlike other serine protease inhibitors, YM-47141 exhibited relatively weak effects on cathepsin G and alpha-chymotrypsin and its inhibitory Ki values were 9.2 x 10(-4) M and 1.3 x 10(-6) M, respectively. It had little, or no inhibitory effect on plasmin, thrombin, trypsin and kallikrein (IC50 > 10(-4) M). The inhibition of HLE by YM-47141 was reversible and of a mixed type.
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PMID:Effect of YM-47141, a new inhibitor produced by Flexibactor sp. Q17897, on elastase. 920 94

SPAAT has previously been shown to be a competitive inhibitor of the model serine protease, chymotrypsin. We now present evidence that SPAAT is likewise a competitive inhibitor of human neutrophil elastase and cathepsin G with Ki's of 15-20 and 40 microM, respectively. The mechanism of this inhibition was investigated by comparing the relative effectiveness of the 23-residue N-terminal fragment of SPAAT (N-SPAAT) to inhibit chymotrypsin and human neutrophil elastase. N-SPAAT, which does not contain the primary chymotrypsin cleavage site, was approximately 10-fold less effective as an inhibitor of chymotrypsin than SPAAT (Ki of 65 microM versus 7.5 microM). In contrast, this fragment, which contains the primary human neutrophil elastase cleavage site, was found to competitively inhibit human neutrophil elastase with a Ki of 24 microM which was comparable to that of SPAAT (Ki = 15-20 microM). Thus it appears that SPAAT is a reversible inhibitor of these enzymes rather than an irreversible, stoichiometric one like its parent protein, AAT. Such fragmentation of AAT, however, might provide a mechanism whereby a cascade of decreasingly potent, but increasingly specific SPAAT-related inhibitory peptides could be generated. These results further substantiate the view that SPAAT may play a role in vivo in the protection of extracellular proteins from inappropriate attack by proteases which are elevated during various pathophysiological conditions.
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PMID:Inhibition of human serine proteases by SPAAT, the C-terminal 44-residue peptide from alpha1-antitrypsin. 921 22

A series of novel synthetic peptides, containing a C-terminal beta-amino alcohol linked to p-methoxybenzoic acid via an ester linkage, have been prepared and tested as inhibitors against typical members of the serine protease family. For example, the sequences Ac-Val-Pro-NH-CH-(CH2-C6H5)-CH2O-CO-C6H4-OCH3 (I) and Ac-Val-Pro-NH-CH-[CH-(CH3)2]-CH2O-CO-C6H4-OCH3 (II), which fulfil the known primary and secondary specificity requirements of chymotrypsin and elastase respectively, have been found to behave as exceptionally potent irreversible inactivators of their respective target protease. Thus I was found to inactivate chymotrypsin with an overall second-order rate constant (k2/Ki) of approx. 6.6x10(6) M-1. s-1, whereas II is an even more potent inactivator of human neutrophil elastase, exhibiting a second-order rate constant of inactivation of approx. 1.3x10(7) M-1.s-1. These values represent the largest rate constants ever reported for the inactivation of these proteases with synthetic peptide-based inactivators. On prolonged incubation in substrate-containing buffers, samples of the inactivated proteases were found to regain activity slowly. The first-order rate constants for the regeneration of enzymic activity from chymotrypsin and human neutrophil elastase inactivated by I and II respectively were determined to be approx. 5.8x10(-5) s-1 and approx. 4.3x10(-4) s-1. We believe that the most likely mechanism for the inactivation and regeneration of enzymic activity involves the formation and subsequent slow hydrolysis of long-lived acyl enzyme intermediates.
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PMID:Peptidyl inverse esters of p-methoxybenzoic acid: a novel class of potent inactivator of the serine proteases. 927 Oct 79

Chronic wound healing states are often associated with aging, and despite the increased number of aged patients with nonhealing wounds, controversy still exists concerning the effects of age on wound repair. Our previous work showed that in both venous ulcers in humans and acute wounds in aged animals, fibronectin, an early component in granulation tissue, is deficient compared to normal skin and acute wounds in healthy young animals, respectively. In the present study, we have determined the protease responsible for fibronectin degradation by analyzing tissue taken from the margins of chronic venous ulcers and standardized acute cutaneous wounds collected from a large cohort of "Health status"-defined aged human subjects (screened as per the SENIEUR protocol). When tissue samples were subjected to fibronectin zymography, the main protease involved in the breakdown of fibronectin in both venous ulcers and acute wounds of elderly subjects was found to be a serine protease with a molecular weight of approximately 30 kd. This protease was identified as neutrophil elastase by immunoblotting. In tissue biopsies, elastase was localized to granulocytes by immunocytochemical techniques and shown to be present in greater quantities in venous ulcers and Day-7 and -14 healing acute wounds of healthy aged subjects relative to those of young subjects. The highest quantities were found in acute wounds of elderly women. Our results suggest that the process of aging in healthy human subjects is associated with an up-regulation of elastase during acute wound healing and that an abnormality in down-regulation of this protease could be partially responsible for the transition to chronic wound healing states in the aged.
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PMID:Up-regulation of elastase in acute wounds of healthy aged humans and chronic venous leg ulcers are associated with matrix degradation. 931 51

Neutrophils play an important part in the development of acute inflammatory injury. Human neutrophils contain high levels of the serine protease elastase, which is stored in azurophilic granules and is secreted in response to inflammatory stimuli. Elastase is capable of degrading many components of extracellular matrix [1-4] and has cytotoxic effects on endothelial cells [5-7] and airway epithelial cells. Three types of endogenous protease inhibitors control the activity of neutrophil elastase, including alpha-1 protease inhibitor (alpha-1PI), alpha-2 macroglobulin and secreted leukoproteinase inhibitor (SLPI) [8-10]. A disturbed balance between neutrophil elastase and these inhibitors has been found in various acute clinical conditions (such as adult respiratory syndrome and ischemia-reperfusion injury) and in chronic diseases. We investigated the effect of NX21909, a selected oligonucleotide (aptamer) inhibitor of elastase, in an animal model of acute lung inflammatory disease [11-14]. This inhibitor was previously selected from a hybrid library of randomized DNA and a small-molecule irreversible inhibitor of elastase (a valine diphenyl ester phosphonate, Fig. 1), by the blended SELEX process [15]. We show that NX21909 inhibits lung injury and neutrophil influx in a dose-dependent manner, the first demonstration of efficacy by an aptamer in an animal disease model.
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PMID:Protective effects of an aptamer inhibitor of neutrophil elastase in lung inflammatory injury. 938 99

A series of thieno[2,3-d][1,3]oxazin-4-ones was synthesized and evaluated in vitro for inhibitory activity toward human leukocyte elastase. New synthetic routes to 2-alkoxy-, 2-alkylthio-, and 2-sec-amino-substituted derivatives are reported. This study demonstrates the versatility of 2-aminothiophenes prepared by Gewald reaction as a synthetic entry to serine protease-inhibiting, fused 1,3-oxazin-4-ones. Introduction of ethoxy, n-propoxy, and ethylthio groups at C-2 delivered the most potent inhibitors of this series with Ki values lower than 11 nM. Kinetic studies and product analyses revealed the formation of acyl-enzymes as a result of the attack of the active site serine at the carbon C-4 and subsequent deacylation. This mode of action is similar to the inhibition of serine proteases by 4H-3,1-benzoxazin-4-ones. Replacement of the benzene ring in benzoxazinones by a (substituted) thiophene led to improved hydrolytic stability and retained inhibitory potency.
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PMID:Novel thieno[2,3-d][1,3]oxazin-4-ones as inhibitors of human leukocyte elastase. 957 99

PU.1 is a transcription factor present in B-cells and macrophages. Here, we report our studies on the role of PU.1 in myelopoiesis using human neutrophil elastase (HNE) as a model. HNE, a component of the primary granules of mature granulocytes, is a serine protease which is transcriptionally restricted to the late promyelocytic stage of granulocytic maturation. The first 200 bp of the HNE promoter directs myeloid specific expression of a reporter gene and a 30-bp element within this region was been identified as the major determinant of myeloid specific expression [S. Srikanth, T. Rado, A 30-bp element is responsible for the myeloid specific activity of the human neutrophil elastase promoter, J. Biol. Chem. 269 (1994) 32626-32632.]. We now show that the B-cell and macrophage specific transcription factor, PU.1, binds to the PU.1 consensus site within the 30-bp element to activate transcription. Substitution mutations within this recognition sequence results in the loss of PU.1 binding and in a 90% decrease in promoter activity in myeloid cells. Cotransfection of PU.1 and a reporter gene controlled by the HNE promoter into non-myeloid HeLa cells resulted in activation of reporter gene transcription.
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PMID:PU.1 regulates the expression of the human neutrophil elastase gene. 968 20


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